Art of recovering potash



earn ens a'r rice.

WILLIAM HOSKINS, OF CHICAGO, ILLINOIS.

ART OF REGOVERING POTASH.

No Drawing.

To all whom it may concern Be it known that I, WILLIAM HosKINs, acitizen of the United States, residing at Chicago, in the county of Cookand State of Illinois, have invented a new and useful Improvement in theArt of Recovering Potash, of which the following is a specification.

My invention relates to the art of recovering potassium and itscompounds and will be fully understood from the following specification.

In brief, I have discovered that the ordinary grades of coal used forfuel in industrial furnaces and the like, and such, for instance, asIllinois and Indiana bituminous coal, may, under certain conditions,form a supply for potassium and its compounds.

chemical composition of coal, it may have been previously known thatcoal contains traces of potassium as well as traces of most of thecommon elements native to the soil or to the various sub-surface strataof the local-v ity in which the coal occurs, such traces of anexceedingly large number of elements appearing from a spectrum analysisof al-,- most any sample of coal, it is certain that the presence ofpotassium was either wholly unknown or was regarded as entirely negli.gible. An examination of the writings of the recognized authorities onthe subject demonstrates that if potassium had, in fact, been discoveredin coal, it was completely ignored in the statements of analysis.

So also the ash, or residue, resulting from the combustion of coal ofevery common variety, has been repeatedly subjected to the most carefulstudy, but here, also, there is, no indication that anything more thanquantitatively undeterminable traces of potassium could be found.

I have discovered, however, that the ordinary grades of coal referredto, when burned in the usual manner in the furnaces of boilers, form atechnically valuable source of supply of potassium. The minutequantities or traces of potassium present in the native coal arevolatilized by the heat of combustion, and are carried out of thecombustion chamber along with a relatively small proportion of unburnedcarbon, ash, and small quantities of other substances.

Specification of Letters Patent. Patentgfl Jung 1'7, 11919,, Applicationfiled January 12, 1917. Serial No. 142,099.

This matter, which is either solid, or condensable, and whichcontinuously passes out of the combustion chamber, is relatively smallin proportion to the mass of coal burned, but in the aggregate amountsto a very considerable quantity, especially in large industrialestablishments, such, for instance, as public service electric light andpower generating stations. The solid and condensable matter carried outof the com- I bustion chamber of the furnace collects or deposits, inthe first instance, immediately behind the bridge wall, or in thebreeching or equivalent structure of the furnace. accu mulating in theform of a friable slag which is periodically broken up and cleaned outby technically useful and valuable source of j the furnace attendants. Acertain further proportion of the solid or condensable con- Although, inView of the commercial im portance of the matter, and ofthe deep studyand widespread prevalent knowledge of the tituents carried along by thecombustion gases escape deposition at this place, however, and is caughtas soot on the walls of the economizers, fiues, stacks or other surfacesover which the combustion gases pass before being vented to theatmosphere.

The slag and soot deposited from the out going combustion gases in themanner described, I find to contain workable quantities of potassium orits compounds. Apparently, the process of combustion as ordinarilycarried out in the manner above described, automatically affects theconcentration of whatever potassium may have been present in theoriginal coal, and this concentration process is so effective thatquantities of potassium, so minute as to be quantitativelyundeterminable in the original coal, appear as workable percentages inthe slag and soot concentrate.

For example, it is found that a certain industrial establishment burnsin the neighborhood of 96,000 tons of coal per month, producing in thatperiod 900 tons of slag and 55 tons of soot. By analysis theseconcentrates are found to contain the following proportion of potassium(figured as K 0) Slag .60% Soot 1.75

Of this quantity of potash approximately 7 5% may be recovered by merelyleaching with warm or hot water. The total recovery of potash from theplant in question would, therefore, be of the order of 5?; tons permonth,

The foregoing example is representative process of combustion-as carriedout in industrial furnaces, the minute quantities or traces of potassiumin the native coal become automatically concentrated in the solid orcondensable matter deposited by the combustion gases, the concentrationproceeding so far as to afford a source of potassium which may betechnically utilized by the simple expedient of leaching, the resultantpotash solution being evaporated to dryness by waste heat from thefurnaces which produce the raw material, or the potash being recoveredin any other appropriate manner.

111 view ofthe fact that the industrial furnaoes of this countrycontinuously consume hundreds of millions of tons of coal in each year,such coal consumption, according to the ordinary methods, necessarilyresulting in the formation of a potassium concentrate containingworkable quantities of cal importance.

What I claim as new and deslre to secure by Letters Patent is:

1. The method of obtaining potash, which consists in collecting thesolid andcondensable matter carried by the gases resulting from thecombustion of coal in industrial furnaces, and extracting the potashfrom the said solid matter.

2. The method of obtaining potash, which consists in collecting thesolid and condensable matter carried by the gases resulting from thecombustion of coal in industrial furnaces, and leaching out the potashfrom said solid matter. W

3. The method of obtaining potash, which consists in collecting thesolid and) condensalble matter carried by the gases resulting from thecombustion of coal in industrial furnaces, leaching out the potash fromsaid solid matter, and evaporating the potash solution thus obtained bythe heat resulting from the combination of the said coal.

WILLIAM HOSKINS.

Gopies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington. D. C.

